ProtologueHort. bengal.: 70 (1814).FamilyCucurbitaceae Chromosome number2n = 26SynonymsCucumis acutangulus L. (1753).Vernacular namesRidged gourd, angled loofah, ribbed gourd, Chinese okra, silk squash (En). Papengaye, liane torchon (Fr). Lufa riscada (Po). Mdodoki (Sw).Origin and geographic distributionLuffa acutangula is believed to have originated in India, where wild types still occur, but has now spread pantropically to all areas with a high rainfall. It is cultivated and locally naturalized in West Africa, from Sierra Leone to Nigeria. It is cultivated from the coastal areas to the semi-dry savanna, e.g. in Sierra Leone, Côte d’Ivoire, Ghana, Benin and Nigeria. In East Africa ridged gourd is grown on a small scale near the big cities as an exotic vegetable for consumers of Asian origin, and it is also locally cultivated and naturalized in Madagascar, Réunion and Mauritius. In southern and eastern Asia it is a widely cultivated vegetable.UsesImmature fruits of less-bitter cultivars of Luffa acutangula are used as a vegetable. They are cooked or fried and used in soups and sauces. Occasionally, the stem tops with young leaves and flower buds are used as a leafy vegetable. In South-East Asia, ridged gourd is a popular vegetable because of the mildly bitter flavour, the slightly spongy texture and sweet juiciness. Young fruits of sweet cultivars are also eaten raw and small fruits are sometimes pickled. The seeds yield an edible oil that is, however, sometimes bitter and toxic.In some parts of West Africa a leaf extract of ridged gourd is applied on sores caused by guinea worms to kill the parasite. Leaf sap is also used as an eyewash to cure conjunctivitis. The fruits and seeds are used in herbal preparations for the treatment of venereal diseases, particularly gonorrhoea. In Mauritius the seeds are eaten to expel intestinal worms and the leaf juice is applied to skin affections such as eczema. The plant including the seed is insecticidal. Mature fruits when harvested dry are processed into sponges and used for scrubbing the body while bathing or for domestic purposes, such as washing of cooking utensils, and as filters for local drinks such as palm wine. Industrial use is made of these fibres for making hats. However, the sponge gourd (Luffa cylindrica (L.) M.Roem., synonym: Luffa aegyptiaca Mill.) is preferred for making sponges because its fibre is easier to extract. The trailing stem is used as temporary tying rope for firewood and crops to be carried home. The plant is occasionally used as an ornamental climber for enclosures.Production and international tradeRidged gourd is mainly produced as a home garden crop. Thailand exports ridged gourd to western Europe as a vegetable for the Asian communities. Japan and Brazil are the main exporters of loofah sponges mostly to the United States, but these are mainly from sponge gourd. In West Africa mature fruits of ridged gourd or sponge gourd are sold as sponges in street markets and supermarkets.PropertiesThe composition of ridged gourd fruits per 100 g edible portion (tough skin removed, edible portion 62%) is: water 94.2 g, energy 70 kJ (17 kcal), protein 0.8 g, fat 0.1 g, carbohydrate 3.3 g, fibre 1.7 g, Ca 12 mg, P 32 mg, Fe 0.3 mg, carotene 26 μg, thiamin 0.07 mg, riboflavin 0.02 mg, niacin 0.4 mg, folate 37 μg, ascorbic acid 3 mg. The composition of young Luffa leaves per 100 g edible portion is: water 89 g, protein 5.1 g, carbohydrate 4 g, fibre 1.5 g, Ca 56 mg, Fe 11.5 mg, β-carotene 9.2 mg, ascorbic acid 95 mg (Holland, B., Unwin, I.D. & Buss, D.H., 1991). The oil content in the seeds is 26%; the fatty acid composition is: linoleic acid 34%, oleic acid 24%, palmitic acid 23% and stearic acid 10%.Two trypsin inhibitors and a ribosome inactivating peptide (luffangulin) have been isolated from ridged gourd seeds. The glycoprotein luffaculin, also isolated from the seeds, exhibits abortifacient, antitumour, ribosome inactivating and immunomodulatory activities.Adulterations and substitutesYoung fruits of sponge gourd (Luffa cylindrica) are used as a substitute for ridged gourd as a vegetable, although much less popular.DescriptionMonoecious, annual, climbing or trailing herb, with acutely 5-angled stem; tendrils up to 6-fid, hairy. Leaves alternate, simple; stipules absent; petiole up to 15 cm long; blade broadly ovate to kidney-shaped in outline, 10–25 cm × 10–25 cm, shallowly palmately 5–7-lobed with broadly triangular to broadly rounded lobes, cordate at base, shallowly sinuate-dentate, pale green, scabrous, palmately veined. Male inflorescence racemose with 15–35 cm long peduncle. Flowers unisexual, regular, 5-merous, 5–9 cm in diameter; receptacle tube obconic below, expanded above, c. 0.5 cm long, lobes triangular, 1–1.5 cm long; petals free, pale yellow; male flowers with 3 free stamens inserted on the receptacle tube, connectives broad; female flowers solitary, on pedicels 2–15 cm long, with inferior, densely pubescent, longitudinally ridged ovary, stigma 3-lobed. Fruit a club-shaped, dry and fibrous capsule 15–50 cm × 5–10 cm, acutely 10-ribbed, brownish, dehiscent by an apical operculum, many-seeded. Seeds broadly elliptical in outline, compressed, up to 1.5 cm long, smooth, dull black.Other botanical informationLuffa comprises 7 species, 4 of these native to the Old World tropics and 3 somewhat more distantly related species indigenous to South America.In Luffa acutangula 3 varieties have been distinguished: var. acutangula, the large-fruited cultivated types; var. amara (Roxb.) C.B.Clarke, a wild or feral type with extremely bitter fruits and confined to India; and var. forskalii (Harms) Heiser & E.E.Schill., confined to Yemen, where it occurs wild or possibly as an escape. Luffa acutangula cultivars grown as vegetables have larger fruits and are less bitter than the wild types. In West Africa local cultivars are used as vegetables, whereas in East Africa commercial growers use improved cultivars imported from Asian countries for the Asian customers.Growth and developmentSpontaneous growth of plants commences with the beginning of the rainy season. Flowering and fruiting take place throughout the rainy season, while fruits mature and seed dispersal commences as the whole plants become dry at the peak of the dry season. In cultivation, seedlings emerge 4–7 days after sowing after soaking the seeds in cold water overnight to soften the hard seedcoat. Ridged gourd tends to be day-neutral. Flowering starts 6–10 weeks after sowing. Initially male flowers are produced, later also female ones at a ratio of male to female flowers of about 40:1. This ratio can be changed by chemical treatment. The flowers open in the evening and the stigmas have been found to remain receptive from a few hours before to 36–60 hours after anthesis. The flowers are cross-pollinated by many insects, including bees, butterflies and moths.EcologyRidged gourd may be common as a spontaneous plant on abandoned land, as a fallow crop and on garbage heaps. Unlike many other cucurbits it grows well in tropical lowlands. It prefers seasonal climates because dry-season planting is more successful than wet-season planting. In Africa it thrives in the dry forest or moist savanna area, around 8–10°N. Outside these latitudes, too much rain or excessive dryness often affect the development of the fruits. In humid areas growth is directed towards the production of leaf biomass, whereas under dry conditions the energy is directed towards abundant flowering. Too much heavy rainfall during flowering and fruiting leads to fruit rot. Frost is not tolerated. Ridged gourd prefers a well -drained soil with a high organic matter content and a pH of 6.5–7.5.ManagementIn commercial cultivation the crop needs good care. Planting on raised beds assures good drainage in the rainy season. Irrigation is required during dry conditions at regular intervals, particularly before the flowering period. NPK fertilizer is applied to enhance growth, flowering and fruit formation. A basal dressing of NPK (e.g. 14–14–14) at the rate of 25 g/hill can be given, followed by side dressings of 20 g/hill of urea or NPK at two-week intervals. Lateral stems are pruned if they grow too abundantly. Some top and leaf pruning may promote flower and fruit development, resulting in a higher yield. For optimal production the number of fruits per stem may be limited to 20–25. For the spontaneous plants of abandoned farmland or on refuse dumps, hardly any management care is given.Propagation and plantingRidged gourd is normally grown on supports or trellises up to 3 m high. During the dry season it may also be allowed to trail on the ground, but this practice lowers the yield and quality. The seeds are sown on mounds or ridges, 2–3 seeds per hill, 50–60 cm apart in the row and 200 cm between the rows in a trellised system. Without support, 300 cm between the rows can be practised, or about one hole per m each way. Alternatively, seedlings may be raised in containers and transplanted. The 1000-seed weight is around 90 g. For direct sowing 2–3 kg seed is needed per ha, for transplanting 1–1.5 kg. In the Philippines, a planting distance of 2 m × 2 m is practised for a superior F1 hybrid, with a seed requirement of only 500 g/ha.Diseases and pestsRidged gourd is not very susceptible to diseases and pests. Powdery mildew (Erysiphe cichoracearum) and downy mildew (Pseudoperonospora cubensis) are reported. Fruits rot easily in contact with wet soil. In South-East Asia, the larvae of fruit flies (Dacus spp.) may damage young fruits; a high infection of thrips may cause stunted growth, and also caterpillars, leaf miners and aphids are reported as pests.HarvestingYoung immature fruits of 300–400 g are picked 12–15 days after fruit set. Fruits can be picked every 3 days throughout the fruiting season, by hand or with a knife. Individual plants may produce 15–20 fruits; yield declines after 8–13 weeks of harvesting. For sponge production, the fruits are left for two months on the vines till turning brown. For seed production, the seeds are shaken out of the completely dry fruits.YieldLandraces produce 10–15 t/ha. An average yield of 27 t/ha of young fruits is reported for hybrid cultivars in the Philippines under good management.Handling after harvestImmature fruits of ridged gourd are easily damaged. For long distance transport, the fruits have to be carefully packed. The fruits can be stored for 2–3 weeks at 12–16°C. The processing of sponges from the ripe fruits involves immersing the fruit in running water until the rind disintegrates and disappears, then the pulp and seeds are washed out, the sponges are bleached with hydrogen peroxide and dried in the sun.Genetic resourcesGermplasm collections of Luffa acutangula are kept at genebanks in India and Taiwan, at the Institute for Plant Breeding in the Philippines, and in Nigeria at the National Centre for Genetic Resources and Biotechnology (NACGRAB) at Ibadan.BreedingMany local cultivars are found in the Asian countries and improved cultivars are available from several seed companies. Populations are very variable. F1 hybrid cultivars are used in several Asian countries. East-West Seed Company in Thailand developed F1 hybrids for tropical lowland with good market quality, e.g. pale or dark green fruits, short (35 cm) to long (50 cm) fruits. Malika F1 is a hybrid with high disease tolerance and especially suited for the rainy season.ProspectsRidged gourd is a high yielding and easy to cultivate vegetable. Breeding and production technology research combined with market development might give it a chance to develop into a market vegetable of importance in Africa, as in Asian countries. The use of fibre from the mature fruits and the use in agroforestry as a plant for soil rehabilitation with a heavy production of leaf biomass might be investigated.Major references• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, United Kingdom. 960 pp. • Grondin, I., Smadja, J. & Armougom, R., 2002. Les triacylglycerols des huiles de graines de quatre Cucurbitacees tropicales des genres Lagenaria et Luffa. OCL-Oleagineux, Corps Gras, Lipides 9(2–3): 169–173. • Heiser, C.B. & Schilling, E.E., 1990. The genus Luffa: A problem in phytogeography. In: Bates, D.M., Robinson, R.W. & Jeffrey, C. (Editors). Biology and utilization of the Cucurbitaceae. Comstock, Cornell University Press, Ithaca, United States. pp. 120–133. • Holland, B., Unwin, I.D. & Buss, D.H., 1991. Vegetables, herbs and spices. The fifth supplement to McCance & Widdowson’s The Composition of Foods. 4th Edition. Royal Society of Chemistry, Cambridge, United Kingdom. 163 pp. • Huyskens, S., Mendlinger, S., Benzioni, A. & Ventura, M., 1993. Optimization of agrotechniques in the cultivation of Luffa acutangula. Journal of Horticultural Science 68(6): 989–994. • Jansen, G.J., Gildemacher, B.H. & Phuphathanaphong, L., 1993. Luffa P. Miller. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 194–197. • Martin, F.W., 1979. Vegetables for the hot humid tropics. Part 4. Sponge and bottle gourds, Luffa and Lagenaria. Science and Education Administration, United States Department of Agriculture, New Orleans, United States. 19 pp. • Purseglove, J.W., 1968. Tropical Crops. Dicotyledons. Longman, London, United Kingdom. 719 pp. • Robinson, R.W. & Decker-Walters, D.S., 1997. Cucurbits. CAB International, Wallingford, United Kingdom. 226 pp. • Watt, J.M. & Breyer-Brandwijk, M.G., 1962. The medicinal and poisonous plants of southern and eastern Africa. 2nd Edition. E. and S. Livingstone, London, United Kingdom. 1457 pp.Other references• Adebisi, A.A. & Ladipo, D.O., 2000. Evaluation of the utilization spectrum of some Cucurbits in South West Nigeria. CENRAD Development Series 07. CENRAD, Ibadan, Nigeria. 14 pp. • Adegoke, E.A., Akinsaya, A. & Naqvi, H.Z., 1968. Studies of Nigeria medicinal plants: A preliminary survey of plant alkaloid. Journal of the West African Science Association 13: 13–33. • Central Queensland University, 2003. Luffa. [Internet] http://www.ahs.cqu.edu.au/info/science/psg/AsianVeg/Luffa.html. Accessed 10 July 2003. • Chakravarty, H.L., 1968. Cucurbitaceae of Ghana. Bulletin de l’Institut Fondamental d’Afrique Noire, sér. A, 30: 400–468. • Fernando, L.N. & Grün, I.U., 2001. Headspace-SPME analysis of volatiles of the ridge gourd (Luffa acutangula) and bitter gourd (Momordica charantia) flowers. Flavour and Fragrance Journal 16(4): 289–293. • Huyskens, S., 1991. Morphological, physiological and biochemical aspects in the cultivation of two pantropical cucurbits: Luffa acutangula (L.) Roxb. and Momordica charantia L. Doctoral thesis, Rheinischen Friedrich-Wilhelms Universität zu Bonn, Bonn, Germany. 203 pp. • Irvine, F.R., 1952. Food Plants of West Africa. Lejeunia 16: 27–51. • Soladoye, M.O., 1985. A checklist of Nigeria cucurbits (family Cucurbitaceae). Research paper, Forest Series No 56. Forestry Research Institute of Nigeria, Ibadan, Nigeria. 13 pp.Sources of illustration• Jansen, G.J., Gildemacher, B.H. & Phuphathanaphong, L., 1993. Luffa P. Miller. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 194–197.Author(s)